Abstract:
Carotid endarterectomy is the main way to combat atherosclerosis of the carotid arteries, which disrupts cerebral circulation. The generally accepted marker of atherogenesis risk are hemodynamic indices associated with near-wall shear stress. The purpose of the work is to conduct a comparative analysis of hemodynamic indices in various carotid bifurcation models. The influence of a virtual change in the geometric shape of the model in order to optimize hemodynamic indices is also being studied. On the basis of computed angiography data, carotid bifurcation models are constructed, in which critical zones of hemodynamic indices are built using computational fluid dynamics. A comparative analysis of the critical zones for different classes of models is carried out. Comparison of averaged indices for critical zones between \'normal\' and post-operative groups gave more than 5-x worse results for the latter. The same results for the near-bifurcation parts of the zones give a 25% better result for postoperative models. Virtual \'removal\' of insignificant plaques leads to a deterioration of the indices of up to 40% in the places of the plaque\'s former location. The described method makes it possible to build the indices critical zones and compare them for various types of models. A technique for virtual changing the shape of a vessel (virtual surgery) is proposed. The novelty of the approach lies in the use for comparative analysis both real vessel models and hypothetical \'improved\' virtual ones, as well in the proposed division of post-operative model\'s critical zones into subzones of different genesis.
摘要:
颈动脉内膜切除术是对抗颈动脉粥样硬化的主要方法,会破坏大脑循环.动脉粥样硬化风险的普遍接受的标记是与近壁剪切应力相关的血液动力学指标。这项工作的目的是对各种颈动脉分叉模型中的血液动力学指标进行比较分析。为了优化血液动力学指标,还正在研究模型几何形状的虚拟变化的影响。根据计算机血管造影数据,构建颈动脉分叉模型,其中使用计算流体动力学建立血液动力学指标的关键区域。对不同类别模型的临界区进行了比较分析。“正常”组和术后组之间临界区的平均指数的比较得出的结果差了5倍以上。区域的近分叉部分的相同结果为术后模型提供了25%的更好结果。不显著斑块的虚拟“去除”导致斑块以前位置的指数恶化高达40%。所描述的方法使得可以构建指标临界区并将其与各种类型的模型进行比较。提出了一种用于虚拟改变血管形状的技术(虚拟手术)。该方法的新颖性在于使用真实的血管模型和假设的“改进的”虚拟模型进行比较分析,以及将术后模型的临界区划分为不同成因的子区。
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